The United Nations on Tuesday called on states not to “backtrack” on pledges made to host migrants and refugees, including from Syria, in the wake of the attacks in Paris.

“We are concerned about the reactions from some states to end programs being put in place, backtracking from commitments made to manage the refugee crisis,” said UN refugee agency spokeswoman Melissa Fleming.

“Refugees should not be turned into scapegoats and must not become the secondary victims of these most tragic events,” Fleming added, after some EU states indicated they would take a hard line on the migrant crisis following the attacks.

She described as “disturbing” rhetoric from some countries suggesting they might walk back on previously made commitments.

“What’s being threatened is an EU plan to manage the arrival of so many people … We need all the countries in Europe to be on board,” Fleming said.

European populist and far-right leaders have seized on the jihadist attacks in Paris to demand the continent stem the record migrant influx.

Hungary’s parliament on Tuesday gave Prime Minister Victor Orban the green light to challenge in court a quota system on taking in migrants, which was previously agreed by EU governments.

France’s anti-immigration National Front leader Marine Le Pen called for an “immediate halt” to new arrivals, while Germany’s xenophobic PEGIDA movement drew thousands to their latest anti-Islam rally.

Poland’s new right-wing, eurosceptic government, which was sworn in Monday, signaled it would take a harder line on migrants, while honoring previously agreed EU commitments.

Some politicians voicing anti-migrant rhetoric have pointed to the discovery of a Syrian passport near the body of one of the Paris suicide attackers, with French prosecutors saying his fingerprints matched those recorded in October in Greece, the start of the European migrant trail for many.